1. Technical Field
The technology described herein relates generally to wireless networking. More particularly, the technology relates to transmitting signaling information to a plurality of stations (STAs) in a Wireless Local Area Network (WLAN) wherein one or more STAs may utilize different bandwidths.
2. Description of the Related Art
Wireless LAN (WLAN) devices are currently being deployed in diverse environments. Some of these environments have large numbers of access points (APs) and non-AP stations in geographically limited areas. In addition, WLAN devices are increasingly required to support a variety of applications such as video, cloud access, and offloading. In particular, video traffic is expected to be the dominant type of traffic in many high efficiency WLAN deployments. With the real-time requirements of some of these applications, WLAN users demand improved performance in delivering their applications, including improved power consumption for battery-operated devices.
A WLAN is being standardized by the IEEE (Institute of Electrical and Electronics Engineers) Part 11 under the name of “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.” A series of standards have been adopted as the WLAN evolved, including IEEE Std 802.11™-2012 (March 2012) (hereinafter, IEEE Std 802.11). The IEEE Std 802.11 was subsequently amended by IEEE Std 802.11ae™-2012, IEEE Std 802.11aa™-2012, IEEE Std 802.11ad™-2012, and IEEE Std 802.11ac™-2013 (hereinafter, IEEE 802.11 ac).
Recently, an amendment focused on providing a high efficiency WLAN in high-density scenarios is being developed by the IEEE 802.11ax task group. The 802.11.ax amendment focuses on improving metrics that reflect user experience, such as average per station throughput, the 5th percentile of per station throughput of a group of stations, and area throughput. Improvements will be made to support environments such as wireless corporate offices, outdoor hotspots, dense residential apartments, and stadiums.
New multiuser transmission technologies such as Multi-User (MU) Multiple-input Multiple-output (MIMO) and MU Orthogonal Frequency-Division Multiple Access (OFDMA), have received much interest for next-generation Wi-Fi technology. Particularly, OFDMA technology has potential since it does not require an antenna array at an AP.
In OFDMA, several OFDM symbols are sent consecutively at each of a plurality of frequencies. Hence, OFDMA has a frequency or subcarrier dimension and a time, or OFDM symbol index, dimension. Thus, OFDMA uses two-dimensional (2D) time-frequency resources, and a subset of the 2D resources are assigned for unicasting a packet to or from a client. Simultaneously communicating with a plurality of client, such as by using a Down-Link (DL) or Up-Link (UL) OFDMA frame, may improve a medium utilization efficiency of the WLAN.
STAs within a WLAN may be configured to use different bandwidths. For example, a STA capable of using an 80 MHz bandwidth may from time to time be configured to utilize only a 20 MHz or 40 MHz bandwidth for transmission and/or reception to save power.
Communicating with as many STA as possible using a single frame may increase the medium utilization efficiency of the WLAN. For example, aggregating frames for as many STA as possible into a single OFDMA frame may increase the medium utilization efficiency, and may relax a scheduling burden of the AP. In another example, sending signaling information, such as a resource allocation map allocating resources of an OFDMA frame to a plurality of STA, to the plurality of STA using a single OFDMA frame may increase the medium utilization efficiency.
The number of STA that may be communicated with using a single frame may be increased when the single frame supports simultaneous communication with STAs that are contemporaneously configured to utilize different bandwidths from each other.